Animal Species:Smalleye Squaretail, Tetragonurus cuvieri Risso, 1810

The Smalleye Squaretail can be recognised by its distinctive jaws, scalation and body form. It has a widespread distribution in most world oceans.

Head of a Smalleye Squaretail

Head of a Smalleye Squaretail
Photographer: Stuart Humphreys © Australian Museum

Standard Common Name

Smalleye Squaretail

Alternative Name/s

Raven Fish, Squaretail


The Smalleye Squaretail can be recognised by its distinctive jaws, scalation and body form. The lower jaw is very stout and has a single row of fan-like teeth. It is almost totally concealed by the upper jaw when the mouth is closed. The upper jaw has small pointed teeth in a single row. When viewed from the front the mouth opening is diamond-shaped.

The species has a long, slender body that is rounded in cross-section. There are small, ridged scales arranged in spirals around the body. The caudal peduncle is rectangular in cross-section and has two lateral keels on both sides.

Adult Smalleye Squaretails are uniform dark brown to black. The juveniles are grey above and whitish below. This is probably an adaptation to the deepwater habitat of the adult and the surface habitat favoured by juveniles.

Size range

The Smalleye Squaretail grows to 70cm in length.


It has a widespread distribution in most world oceans. In Australia, the Smalleye Squaretail is recorded from New South Wales, Victoria and Tasmania but probably occurs in deep waters off all southern Australian states.

The map below shows the Australian distribution of the species based on public sightings and specimens in Australian Museums. Click on the map for detailed information.  Source: Atlas of Living Australia.

Tetragonurus cuvieri

Distribution by collection data

Ozcam map of Smalleye Squaretail specimens in the Australian Museum.

What does this mean?


Adults live in continental slope waters at depths from 500 m to 600 m.

Feeding and Diet

The species eats jellyfish and salps.

Danger to humans and first aid

At certain times of the year it is reported to be poisonous.



What does this mean?


  1. Gomon, M.F. in Gomon, M.F, C.J.M. Glover & R.H. Kuiter (Eds). 1994. The Fishes of Australia's South Coast. State Print, Adelaide. Pp. 992.
  2. Hoese, D.F., Bray, D.J., Paxton, J.R. & G.R. Allen. 2006. Fishes. In Beesley, P.L. & A. Wells. (eds) Zoological Catalogue of Australia. Volume 35. ABRS & CSIRO Publishing: Australia. parts 1-3, pages 1-2178.
  3. Last, P.R, E.O.G. Scott & F.H. Talbot. 1983. Fishes of Tasmania. Tasmanian Fisheries Development Authority. Pp. 563.
  4. May, J.L & J.G.H. Maxwell. 1986. Field guide to Trawl Fish from Temperate Waters of Australia. CSIRO. Pp. 492.

Mark McGrouther , Senior Fellow
Last Updated:

Tags Fishes, Ichthyology, Smalleye Squaretail, Tetragonurus cuvieri, Tetragonuridae, black, grey, long and skinny, 30 cm - 1 m, no pattern, marine, adult,